/*
 * Copyright 2009 Mike Cumings
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.kenai.jbosh;

/**
 * Abstract base class for attribute implementations based on {@code Integer}
 * types. Additional support for parsing of integer values from their
 * {@code String} representations as well as callback handling of value validity
 * checks are also provided.
 */
abstract class AbstractIntegerAttr extends AbstractAttr<Integer> {

	/**
	 * Creates a new attribute object.
	 * 
	 * @param val
	 *            attribute value
	 * @throws BOSHException
	 *             on parse or validation failure
	 */
	protected AbstractIntegerAttr(final int val) throws BOSHException {
		super(Integer.valueOf(val));
	}

	/**
	 * Creates a new attribute object.
	 * 
	 * @param val
	 *            attribute value in string form
	 * @throws BOSHException
	 *             on parse or validation failure
	 */
	protected AbstractIntegerAttr(final String val) throws BOSHException {
		super(parseInt(val));
	}

	/**
	 * Utility method intended to be called by concrete implementation classes
	 * from within the {@code check()} method when the concrete class needs to
	 * ensure that the integer value does not drop below the specified minimum
	 * value.
	 * 
	 * @param minVal
	 *            minimum value to allow
	 * @throws BOSHException
	 *             if the integer value is below the specific minimum
	 */
	protected final void checkMinValue(int minVal) throws BOSHException {
		int intVal = getValue();
		if (intVal < minVal) {
			throw (new BOSHException("Illegal attribute value '" + intVal
					+ "' provided.  " + "Must be >= " + minVal));
		}
	}

	/**
	 * Utility method to parse a {@code String} into an {@code Integer},
	 * converting any possible {@code NumberFormatException} thrown into a
	 * {@code BOSHException}.
	 * 
	 * @param str
	 *            string to parse
	 * @return integer value
	 * @throws BOSHException
	 *             on {@code NumberFormatException}
	 */
	private static int parseInt(final String str) throws BOSHException {
		try {
			return Integer.parseInt(str);
		} catch (NumberFormatException nfx) {
			throw (new BOSHException(
					"Could not parse an integer from the value provided: "
							+ str, nfx));
		}
	}

	/**
	 * Returns the native {@code int} value of the underlying {@code Integer}.
	 * Will throw {@code NullPointerException} if the underlying integer was
	 * {@code null}.
	 * 
	 * @return native {@code int} value
	 */
	public int intValue() {
		return getValue().intValue();
	}

}
